Until recent time I have been using Inkscape to draw technical diagrams for different documents and articles I write. However now I think I have found the best tool for such tasks. DIA is a diagram creation program which is inspired by Microsoft Visio. DIA is the perfect tool for preparing very high quality sketches for technical documents.
Since most of the time I use Latex to prepare my documents, I need all the diagrams and graphics in special formats that can be included in Latex documents. For example When preparing research papers using Latex templates most of the times I had to convert my images and documents to EPS file format since the Latex template for the particular conference or journal needs the graphics in that format. What I used to do in such situations is to convert the images and diagrams using an on-line file converter to the EPS format. DIA tool supports so may file formats so that we can export our diagrams to any of them.
DIA can be installed using the software center or otherwise using the command line by issuing the following command.
sudo apt-get install dia
Enjoy preparing quality diagrams for your research papers and technical documents!